import 'package:flutter/material.dart';

/// Flutter code sample for [ExpansionPanelList].

void main() => runApp(const ExpansionPanelListExampleApp());

class ExpansionPanelListExampleApp extends StatelessWidget {
  const ExpansionPanelListExampleApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(title: const Text('ExpansionPanelList Sample')),
        body: const ExpansionPanelListExample(),
      ),
    );
  }
}

// stores ExpansionPanel state information
class Item {
  Item({
    required this.expandedValue,
    required this.headerValue,
    required this.value,
    required this.canTapOnHeader,
  });

  String expandedValue;
  String headerValue;
  int value;
  bool canTapOnHeader;
}

List<Item> generateItems(int numberOfItems) {
  return List<Item>.generate(numberOfItems, (int index) {
    bool canTapOnHeader = index > 3;
    return Item(
      headerValue: 'Panel $index canTapOnHeader=${canTapOnHeader.toString()}',
      expandedValue: 'This is item number $index',
      value: index,
      canTapOnHeader: canTapOnHeader,
    );
  });
}

class ExpansionPanelListExample extends StatefulWidget {
  const ExpansionPanelListExample({super.key});

  @override
  State<ExpansionPanelListExample> createState() =>
      _ExpansionPanelListExampleState();
}

class _ExpansionPanelListExampleState extends State<ExpansionPanelListExample> {
  final List<Item> _data = generateItems(8);

  @override
  Widget build(BuildContext context) {
    return SingleChildScrollView(
      child: Container(
        child: _buildPanel(),
      ),
    );
  }

  Widget _buildPanel() {
    return ExpansionPanelList.radio(
      children: _data.map<ExpansionPanelRadio>((Item item) {
        return ExpansionPanelRadio(
          headerBuilder: (BuildContext context, bool isExpanded) {
            return ListTile(
              title: Text(item.headerValue),
            );
          },
          body: ListTile(
              title: Text(item.expandedValue),
          ),
          value: item.value,
          canTapOnHeader: item.canTapOnHeader,
        );
      }).toList(),
      expandIconColor: Colors.red,
    );
  }
}